Amazon.com: Neurogan GHK Cu Copper Peptide Face Cream 4% Peptides for Skin Firmness & Deep Hydration Daily Facial Moisturizer with 2400 MG GHK Cu, 2oz : Beauty & Personal Care GHK Cu Peptides Benefits for Anti Aging Skin Rejuvenation How to Use With Micro Infusion Topical or SubQ GHK Cu? Same molecule. Very different purposes. Topical you apply it on your skin. Think of it as feeding your skin from the outside. In a 12 week study of GHK Cu Peptide Therapy: The Definitive Clinical Guide to Gene Modulation, Protocols, and Efficacy